package main

import(
  "fmt"
  "time"
  )
  
  func say(s string){
     for i := 0; i < 5; i++{
	   time.Sleep(100 * time.Millisecond)
	   fmt.Println(s)
	 }
  }
  func main(){
   go say("world")
   say("hello")
  }